Means for decreasing the visibility of the wake of automobile torpedoes



June 9, 1925.

. C. DAVIS MEANS FOR DECREASING THE VISIBILITY OF THE WAKE OF AUTOMOBILE -TORPEDOES Filed Nev. 28. 1925 2 Sheets-Sheet 1 .lune 9, 1925. 1,541,689

c. DAVIS -MEANS FOR DECREASING .THE VISIBILITY OF THE WAKE OF AUTOMOBILE TORPEDOES Filed Nov. 2s, 1925 2 sheets-sheenl 2 Patented June 9, 1925.

UiTEn CLEL'AND@Avisa orf.:ENGLEWQODcierre@.lvm/v JERSEY, .nssenoia To immonet. TonPEnoxooMANx on AUGUSTA; Merlijn, A yooarone'rion; or MAINE.

MEANS FOR DECRLEASINGTHE VISIBILITY (Jr-Tian, wenn or AutonomenTonrnnons',

I Appli-cation ined-*Nwember zs-flseaii sei-iai Neyer/,46s.

Tv @ZZ whom-H# mt-3f concern.' Iha'iie 'shown the invention in-vtWo vforms Befit'known thatf'I CILELAND" Davis, a andadalp'ted foruse either With a torpedo citizen oftheUnitedStates; residingiat En.l having: propeller gti-'aids projecting inrfthe gleW-ood Cliffs, countyof'fBe-rgen, and State rear of the propellersorlwithfthe torpedo of'NeivJersey, have;invented'fcertain new in -Wliichfsuch guards are omitted and in 60 and useful\ImprovementsinjMeans -fo-r-De-A Whichthere are no fixed portions ofthetorcreasing the vVisibilityoffthe lVale-of Au; pedo -in the rear of the hollow propeller tomobilelfTorpedoes; andfldoEi liereby-deshaf-tl f cla're the followingto` b'eafullj clearyan'd My' invention: Will be' morefully undereXact description, su'ch as Willen-able` others sto`ocl*aft'er =reference to the'accompanying 65 skilled in the 'art to'whichit 'appertains -todrawings, inwhich: make and use the: same; n Figure lshoWs thetorpedo providedvwith My presentinvention 'relates to improved propelleim `gua-rds with 'af foraminous hose" atmeansy for decreasing the-visibility of `the tached 'th-rough' therearthereof,said hose Wake Ofanto-mobile torpedoes,` which `are beingc-losedat its rear end; driven by compressed air or'othergas Figure 2 is a `sectio-nal vieyvy o-n av-larger lViththepresent' type of' automobile torscale', showing4 the mode-of-attaching.the pedoes, the propellingjpoaver comp-rises a hosefto the vtorpedog'and V tankof air,underveryjhigh pressure, which Figure '8 is a sectionalelevation showing escapes'tlirou'gh' azr'educing valve,v and the the cap-or casing "connectedio ltherear end 75 expanded `air is heated before going Ato the of* the hub ofthe rear propeller'in aniauto-v turbines which drive Athepropellers in remfobile torpedo which is devoid of'propoller verse directions. The escape air after doguards, saidcapi` or casi'ng'rotating with ing its 'Work is generally allowed' to flow saiclliiib=,haiid forming a foraininous cham'- through the.. inne-r .hollow propeller-"shaft beriutogivhieh:thel escapingzair"passeerV 50 and escapes intothesea in the form of large Referring first to "Figsil and25iA repreL bubbles or globules. These bubbles expand sents the main body of the torpedo, which as they rise in the Water and finally burst is constructed of the usual or preferred at the top of the Water causing a very visible type7 and Which is provided with the usual Wake. propeller guards B between which the pro- S This Wake is so apparent under normal pellers C and D are journalled in. the usual. Weather conditions that the approach of the Way. These propeller shafts are in the torpedo may be detected, and the vessel or form of concentric tubes C and D', and the Vessels at Whom it is aimed may readily exhaust air from the engine (not shown) avoid the same by maneuvering. passes through the inner tube or rear pro- Such was found to be the case in the batpeller shaft and ordinarily flows into the tle of Jutland and has been often noted in sea, but according to my invention, I attach practice before and since then. a flexible hose E` Which may be made of I have found that by breaking up the air rubber or other suitable material7 preferably into Very small globules before it is allowed reinforced Wit-h Wire coils F and closed at to escape into the Water, the size and exthe rear end with a cap G, preferably ofy plosive effect of the bubbles and the corogival or pointed construction, so as to reresponding visibility of the Wake of the torduce the resistance, as it is drawn through pedo may largely be decreased, if not actuthe Water. ally eliminated for most practical purposes. This hose is provided with a number of In order to accomplish this result I prosmall openings e of any suitable size, so that vide a suitable foraminous expansion chamthe total area of the openings would be prefber in the rear of the present escape outlet erably greater than the cross-section through for the gases fro-m Which the escaping air the inner propeller shaft. lio-Ws in comparatively minute globules, and These openings are preferably inclined these globules are directed in various direcrearvvards and outvvardsV as shown in Fig. tions through the Water and rise to the sur- 2, so as to create suction as the torpedo face in such a Way as not to have the eX- moves rapidly through the Water, thus to plosive effect of the larger globules or bublessen the back press-ure of the exhaust. bles already referred to, In order to diminish friction the hose 11 may be coated with graphit/e or albumen, or other material which Will tend to lessen the skin friction as it is drawn through the water. c

By vthis arrangement, the escaping air will be broken up into very fine globules before it entersthe water, and it will be directed in various directions into the water and will not rise in large globules or bubbles.

The hoseapplied to the rear of the torpedo, as stated, will also serve to steady the torpedo in its flight through the water after the manner of a tail toa kite. f

In the form of device shown in Fig.v v3, the propeller guards are omitted and there is nothing in the rear portion of the torpedo to which the hose or the like canbeattached, and in such cases I provide a suitable cap attached to the hub of the rear propeller, such as is shown at E. This cap is preferably tapered to follow the contour of the torpedo so as to provide the desired stream lines or fair weather whereby the resistance due to skin friction is largely pansion chamber will not materially increase the back pressure.

In either form of the device as hereinbefore described, the air from the engine escapes through the inner propeller tube and into the expansion chamber, from which it escapes through a number of small perforations, the escaping air being directed in various directions through the water and rising to the surface in due course, wheresmall bubbles only will be formed and the bursting of these small bubbles will not be noticeable under the normal weather conditions that prevail at sea. y

'While I have shown two forms of the invention adapted for use with an automobile torpedo, it willl be obvious that the same general principle may be applied to other forms ofthe device, and` I do not mean to. limit the invention to any particular form or arrangement, except as particularly pointed out in the claim.

Having thus describedk my invention, what I claim and desire to secure by'Let; ters Patent of the United States is:

An attachment VJfor vautomobile torpedoes Y propelled by compressed air or other gas,`

comprising an expansion chamber'ca'rried at ther rear of the'torpedo having a plurality of perforations in its outer walls, the said perforations being inclined outward and rearward to facilitate the exhaust, whereby the escaping air or gas is divided Vinto a numberrof iine streams issuing in divergent directions.

CLELAND DAVIS. 

